SA-106C: It is the steel grade in the ASME SA-106 standard. It is a carbon-manganese steel pipe for large-caliber boilers and superheaters for high temperature. Its chemical composition is simple and similar to 20G carbon steel, but its carbon and manganese content is higher, so its yield strength is about 12% higher than that of 20G, and its plasticity and toughness are not bad. The steel has a simple production process and good cold and hot workability. Using it to replace 20G headers (economizer, water wall, low-temperature superheater and reheater header) can reduce the wall thickness by about 10%, which can save material costs, reduce welding workload, and improve headers The stress difference at start-up .